Using cordless tool batteries to power a drone

<698839253X6D445TD@nospam.org> wrote: 

> And I did put 3 eneloop 1.5 V AAA batteries in it so it is always
> ready. 

Eneloops are 1.2 V per cell. 

Jeff Liebermann <jeffl@cruzio.com> wrote: 

> John Doe <always.look@message.header> wrote: 
>> Jeff Liebermann <jeffl@cruzio.com> wrote: 
>>
>>> I have some opinions on what's wrong with the quadcopter. 
>>> However, I'll wait until I see some voltage and current
>>> measurements and graphs performed in a test stand (like your
>>> chair test).  My guess(tm) is that this sounds like a high
>>> resistance connection between the battery and the ESC
>>> (electronic speed control).  Something seems to be prematurely
>>> announcing that the battery is depleted.  An unwanted voltage
>>> drop in the wiring would do that. 
>>
>> I suspect there's something weird going on in this particular
>> drone, but the low-voltage warning can be set low enough to get
>> full use out of lithium polymer batteries. 
> 
> I can see that I'm not getting through to you.  Please excuse my 
> abrasive, rude, undiplomatic, and short tempered manners.  

That sounds bizarre.

> Here's what you should be doing: 
> 
> 1.  Setup your drone in a manner similar to Jan Panteltje's test 
> chair: 
> <http://panteltje.com/pub/hubsan_h501s_current_test_full_throttle_I
> MG_6290.JPG> 
> 
> 2.  Take DVM and place it across the battery terminals as close to
> the actual battery as possible.  You want to measure the actual
> battery voltage. 
> 
> 3.  Take a 2nd DVM and place it as close to the place where the
> ESC distributes the power to the various motors.  That would be
> the DC input to the ESC.  If the low voltage measurement device is
> located elsewhere, use that connection. 
> 
> 4.  If you have an adapter for your XT60 battery connector for
> current measurement, attach it and also record the current draw
> ever 30 seconds. 
> 
> 5.  Run the drone in the chair at something resembling normal
> flight RPM (not full power).  With a paper pad and pen, record the
> voltages every 30 seconds.  When the low voltage alarm is
> triggered, record the time.  Let it run until the controller or
> ESC declares the battery to be discharged.  Draw a graph.  If my
> guess is correct, the graph will look very strange and that there
> will be a substantial voltage difference between the battery
> terminal voltage and the ESC voltage. 
> 
>> I might try lithium ions for some other drone, but that's it for
>> this one. The lithium-ion pack I made for the controller is
>> working superbly. 
> 
> Really.  Have you calculated what your runtime should be based on
> the average current drain and battery ma-hr rating?  Be sure to
> check the data sheet for the LiIon cells for the ma-hr capacity at
> whatever current your motors are drawing.  How close is your
> flight time to the theoretical runtime? 

My flight time using slightly larger than stock lithium polymers is 
almost 15 minutes, that is GREATER THAN the theoretical flight time of 
12-14 minutes for stock batteries, for this drone.

First person view (FPV) drone flying is a complex hobby. There are 
many other things that need doing. Great hobby for anyone who enjoys 
flight simulation and electronics. The FPV capability can be easily 
installed in remote control cars as well. And tanks...

"Jeff Liebermann"  wrote in message 
news:cbqb1e54jocu531d8fipes1ig11rdbo9ie@4ax.com...
>
>On Sat, 15 Dec 2018 21:14:59 -0500, "Carl"
><carl.ijamesXYZ@ZYXverizon.net> wrote:
>
>>><https://www.ebay.com/sch/i.html?_nkw=MASTECH+MS2109a>
>
>MS2109a data sheet:
><http://www.mastech-group.com/products.php?cate=95&PNo=209>
>
>More Mastech clamp meters:
><http://www.mastech-group.com/products.php?cate=95>
><http://www.mastech-group.com/products.php?cate=95&page=2>
>
>>I've got two Uni-T meters (http://www.uni-trend.com/), both 4000 count
>>models, one a true RMS autoranging DVM and the other a clamp ammeter DVM,
>>model UT204 which does AC and DC and autoranges between 40A and 400A 
>>scales.
>
>True RMS would be nice to have, but is not necessary for what I expect
>to be mostly DC current measurements.
>
>Sigh.  I went to the Uni-T web pile and tried to look for meters.
>Every link link I click returns a "404" (nobody home).  Despite my
>having an uncontrollable urge to buy something immediately, I'll wait
>a day or two for someone to fix the Uni-T web pile or server.

Don't understand this, I checked their site just before posting my first 
reply and again just before posting this, and had no problems.

>
>>I've used it to check starter draw on a car and the output of a 10W solar
>>panel (0.22 A that day) and I'm happy with it.  They have lots of models

I had my other meter in series and both agreed at 0.22A within about 0.01 or 
0.02A.  I was pretty impressed how low the clamp on could go, 40A and 4000 
counts makes the LSD 0.01A.

>>with different features, and lots of sellers on amazon and ebay.  The 
>>Uni-T
>>meters seems to have good accuracy and useful features,
>
>Thanks.  I'll do some reading and see what they have to offer.
>
>>but get their low
>>cost from slow settling times.  Over a second per screen update and often
>>three updates to get a stable reading so 3-5 seconds total.  For my needs
>>that works.
>>
>>If you don't use a clamp-on meter be sure to check the manual for your
>>meter.  Lots of the cheaper meters with a 10A scale bury a truly wimpy 
>>duty
>>cycle in the fine print.  I've seen 15 seconds of 10A measurement followed
>>by ten-plus minutes of required cooldown in at least one of the Uni-T 
>>meters
>>and some other brand I can't remember right now.
>
>Argh.  I didn't realize that this was a problem with DC clamp meters.

I guess I wasn't clear enough, the non-clamp meters can have the duty cycle 
issue but so far as I know none of the clamp on meters have a problem - 
that's whey I said "If you don't use a clamp-on meter ...".

>I just skimmed the Mastech MS2109a manual
><https://panda-bg.com/datasheet/2145-340549-MS2109A-clamp-meter-mastech.pdf>
>but didn't find any mention of a cool down period.
>For sampling rate, it claims:
>"Sampling rate: about 3 times/s, simulation bar 30 times/s."
>Incidentally, the highest count is 5999 which is needed for the 600A
>scale.

-- 
Regards,
Carl Ijames 

"Carl" <carl.ijamesXYZ@ZYXverizon.net> wrote:

> "Jeff Liebermann"  wrote in message 
> news:cbqb1e54jocu531d8fipes1ig11rdbo9ie@4ax.com...

>>Sigh.  I went to the Uni-T web pile and tried to look for meters.
>>Every link link I click returns a "404" (nobody home).  Despite my
>>having an uncontrollable urge to buy something immediately, I'll wait a
>>day or two for someone to fix the Uni-T web pile or server. 
 
> Don't understand this, I checked their site just before posting my first
> reply and again just before posting this, and had no problems.

What browser and OS are you using?

I just checked with Firefox 52.9.0 on XP (same as Jeff) and Firefox 64.0 on 
Win7.

Both gave 404 errors on all links.

Can't even contact them to tell them their site is down.

http://www.uni-trend.com/contact.html

How are you able to get pages?

"Steve Wilson"  wrote in message 
news:XnsA9BA75592A958idtokenpost@69.16.179.23...
>
>"Carl" <carl.ijamesXYZ@ZYXverizon.net> wrote:
>
>> "Jeff Liebermann"  wrote in message
>> news:cbqb1e54jocu531d8fipes1ig11rdbo9ie@4ax.com...
>
>>>Sigh.  I went to the Uni-T web pile and tried to look for meters.
>>>Every link link I click returns a "404" (nobody home).  Despite my
>>>having an uncontrollable urge to buy something immediately, I'll wait a
>>>day or two for someone to fix the Uni-T web pile or server.
>
>> Don't understand this, I checked their site just before posting my first
>> reply and again just before posting this, and had no problems.
>
>What browser and OS are you using?
>
>I just checked with Firefox 52.9.0 on XP (same as Jeff) and Firefox 64.0 on
>Win7.
>
>Both gave 404 errors on all links.
>
>Can't even contact them to tell them their site is down.
>
>http://www.uni-trend.com/contact.html
>
>How are you able to get pages?

Firefox 64.0 32 bit on Win 7 Ultimate 32 bit.  I may have updated Firefox 
between my two posts, or maybe after the second one but definitely 64.0 now 
and it works (can't remember exactly when I told Firefox to update vs. 
posting), and the previous version was the most recent one before 64.0. 
Weirdly, I clicked on your contact link and got a 404 page in Chinese.  Then 
tried just "www.uni-trend.com" and got the home page in english, as always.

-- 
Regards,
Carl Ijames 

"Carl" <carl.ijamesXYZ@ZYXverizon.net> wrote:

> "Steve Wilson"  wrote in message 
> news:XnsA9BA75592A958idtokenpost@69.16.179.23...
>>
>>"Carl" <carl.ijamesXYZ@ZYXverizon.net> wrote:
>>
>>> "Jeff Liebermann"  wrote in message
>>> news:cbqb1e54jocu531d8fipes1ig11rdbo9ie@4ax.com... 
>>
>>>>Sigh.  I went to the Uni-T web pile and tried to look for meters.
>>>>Every link link I click returns a "404" (nobody home).  Despite my
>>>>having an uncontrollable urge to buy something immediately, I'll wait
>>>>a day or two for someone to fix the Uni-T web pile or server. 
>>
>>> Don't understand this, I checked their site just before posting my
>>> first reply and again just before posting this, and had no problems. 
>>
>>What browser and OS are you using?
>>
>>I just checked with Firefox 52.9.0 on XP (same as Jeff) and Firefox 64.0
>>on Win7.
>>
>>Both gave 404 errors on all links.
>>
>>Can't even contact them to tell them their site is down.
>>
>>http://www.uni-trend.com/contact.html
>>
>>How are you able to get pages?
> 
> Firefox 64.0 32 bit on Win 7 Ultimate 32 bit.  I may have updated
> Firefox between my two posts, or maybe after the second one but
> definitely 64.0 now and it works (can't remember exactly when I told
> Firefox to update vs. posting), and the previous version was the most
> recent one before 64.0. Weirdly, I clicked on your contact link and got
> a 404 page in Chinese.  Then tried just "www.uni-trend.com" and got the
> home page in english, as always. 

Thanks for the reply.

I just tried Firefox 64.0 on Win7 Pro 32 bit. Same result using "www.uni-
trend.com". 404

Wierd.

On Sun, 16 Dec 2018 14:17:22 -0000 (UTC), John Doe
<always.look@message.header> wrote:

><698839253X6D445TD@nospam.org> wrote: 
>
>> And I did put 3 eneloop 1.5 V AAA batteries in it so it is always
>> ready. 
>
>Eneloops are 1.2 V per cell. 

Yep, that MIGHT be a problem.  Let's do the numbers.

Discharge curve for a AAA Eneloop NiMH cell:
<http://eneloop101.com/wp-content/uploads/2017/02/BK-4HCC.pdf>
compared with a Duracell CopperTop alkaline AAA cell:
<https://d2ei442zrkqy2u.cloudfront.net/wp-content/uploads/2016/03/MN2400_US_CT1.pdf>

According to the MS2108a manual (Pg 18), the low battery indicator
will complain at 3.7V or 1.23V per cell.  I don't know how much
current the MS2108a will draw from the battery, so I just measured the
current drain on a Radio Shack 22-178 that runs off two AA cells.  I
measured 330 microamps, so a 3 cell arrangement should draw 220
microamps.

Inspecting the graphs for the two types of batteries, and
extrapolating the family of curves to something around 220 microamps,
I find that the alkaline will last >900 hrs before the voltage drops
to 1.23v, while the Eneloop will last about the same >900 hrs.  So, no
benefit in operating time.  

Running the backlighting in the MS2018a might increase the drain to
maybe 10ma, which might cause the battery low warning indicator to
appear.  I suspect that will only a be a problem with an almost
depleted battery.

However, the alkaline cells leak (badly) and are not rechargeable.
Eneloop cells are LSD (low self discharge) and will be ready when you
need to make measurements.  I've been systematically replacing my
various AA and AAA cells with Eneloop NiMH cells, and my 9V batteries
with rechargeable LiIon equivalents.


-- 
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

On Sun, 16 Dec 2018 11:04:57 -0500, "Carl"
<carl.ijamesXYZ@ZYXverizon.net> wrote:

>>Sigh.  I went to the Uni-T web pile and tried to look for meters.
>>Every link link I click returns a "404" (nobody home).  Despite my
>>having an uncontrollable urge to buy something immediately, I'll wait
>>a day or two for someone to fix the Uni-T web pile or server.

>Don't understand this, I checked their site just before posting my first 
>reply and again just before posting this, and had no problems.

Probably the Great Firewall of China at its best.  I have 3 machines
in front of me.  XP, Win 7, and ChromeOS.  XP and Win 7 have Firefox,
Chrome, Internet Exploder, and Vivaldi running.  
<http://www.uni-trend.com>
XP and Win 7 show:
   404 - File or directory not found.
   The resource you are looking for may have been deleted, 
   the name has been changed, or it is temporarily unavailable.
on all browsers as translated from the original Chinese by Google
Translate.  

I also cleared the Firefox and Chrome browser cache and reloaded with
<shift><F5>.  The Acer Chromebook 14 CB3-431-???? only runs Chrome,
but it too returns a 404.  I thought it might be an ISP issue, so I
connected via the neighbors Comcast router.  Same 404.

I also tried 
<https://www.uni-trend.com>
but it would not connect.  I also removed all cookies associated with
uni-trend.com, but the 404 error persisted.  I also clicked on most
everything possible on the home page.  Everything I tried resulted in
a 404 error.

Next, I did a fast port scan using nmap (actually Zenmap).
The server is running Microsoft Windoze Server 2008 Beta 3.  Beta?
Nothing like 10 year old software.  My best guess(tm) is that this
problem lives in the 10 year old server software:
<https://en.wikipedia.org/wiki/List_of_Microsoft_Windows_versions#Server_versions>

# nmap -T4 -F www.uni-trend.com
Starting Nmap 6.46 ( http://nmap.org ) 
at 2018-12-16 14:01 Pacific Standard Time
Nmap scan report for www.uni-trend.com (59.188.250.13)
Host is up (0.31s latency).
Not shown: 97 filtered ports
PORT      STATE SERVICE
80/tcp    open  http
135/tcp   open  msrpc
49154/tcp open  unknown
Nmap done: 1 IP address (1 host up) scanned in 7.64 seconds

Looks like they have a web server with WMI (windoze manglement
interface) enabled to the internet.  I can go on with this, but I
don't feel so good today and would prefer to do something else.

>I guess I wasn't clear enough, the non-clamp meters can have the duty cycle 
>issue but so far as I know none of the clamp on meters have a problem - 
>that's whey I said "If you don't use a clamp-on meter ...".

Oh, now I see.  I was wondering what might be getting warm when using
a clamp type ammeter.  Having smoked a few DVM's in the distant past,
I don't like running high current through them.  I have a small
collection of shunt resistors that work quite well.


-- 
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

On Sun, 16 Dec 2018 15:53:07 -0500, "Carl"
<carl.ijamesXYZ@ZYXverizon.net> wrote:

>Weirdly, I clicked on your contact link and got a 404 page in Chinese.  Then 
>tried just "www.uni-trend.com" and got the home page in english, as always.

Just to clarify things, I was able to get the home page at:
<http://www.uni-trend.com> on all my machines and with all browsers.
The home page worked.  What doesn't work for me are any of the links
and buttons on the home page.

-- 
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

"Jeff Liebermann"  wrote in message 
news:dknd1epbl8r0repr0basd1b1g3u1oc8757@4ax.com...
>
>On Sun, 16 Dec 2018 15:53:07 -0500, "Carl"
><carl.ijamesXYZ@ZYXverizon.net> wrote:
>
>>Weirdly, I clicked on your contact link and got a 404 page in Chinese. 
>>Then
>>tried just "www.uni-trend.com" and got the home page in english, as 
>>always.
>
>Just to clarify things, I was able to get the home page at:
><http://www.uni-trend.com> on all my machines and with all browsers.
>The home page worked.  What doesn't work for me are any of the links
>and buttons on the home page.

I thought you meant that the home page gave you 404.  Before my first reply 
I followed several links from the home page to get specs on a few meters, 
and all worked as expected.  Now, after reading your post I tried that again 
and now I get 404 everywhere, too.  I even went back into my history and 
tried to go to a couple of the pages I visited yesterday and now they also 
give 404.  So, now I can't get anything at their site, either.  I have no 
idea how to make progress so I think I'll give up until the next time I need 
a meter :-).  Good luck if you decide to keep trying.

-- 
Regards,
Carl Ijames